Modal Selection Through Effective Interface Mass With Application to Flexible Multibody Cranktrain Dynamics

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
S. Ricci ◽  
M. Troncossi ◽  
A. Rivola
Keyword(s):  
High Speed ◽  
Mode Selection ◽  
Selection Procedure ◽  
Connecting Rod ◽  
Nonlinear Simulation ◽  
High Rotational Speed ◽  
Hydrodynamic Bearing ◽  
Multibody Model ◽  
High Speed Engine ◽  
Flexible Component

The development of a multibody model of a motorbike L-twin engine cranktrain is presented in this work. The need for an accurate evaluation of the loads acting on the main engine components at high rotational speed makes it necessary to take element flexibility into account in order to capture elastodynamic effects, which might have a major impact on the dynamics of the system. Starting from finite element descriptions of both the crankshaft and the connecting rod, the classical Craig–Bampton (CB) technique is employed to obtain reduced models, which are suitable for the subsequent multibody analysis. A particular component mode selection procedure is implemented based on the concept of effective interface mass, allowing an assessment of the accuracy of the reduced model prior to the nonlinear simulation phase. Bearing dynamics also plays an important role in such a high-speed engine application: angular contact ball bearings are modeled according to a 5DOF nonlinear scheme in order to grasp the main bearings behavior while an impedance-based hydrodynamic bearing model is implemented providing an enhanced operation prediction at big end locations. The assembled cranktrain model is simulated using a commercial multibody software platform. Numerical results demonstrate the effectiveness of the procedure implemented for the flexible component model reduction. The advantages of this technique over the traditional mode truncation approach are discussed.

Lubrication Analysis of a Connecting-Rod Bearing in a High-Speed Engine. Part I: Rod and Bearing Deformation

2004 ◽  
Vol 47 (2) ◽  
pp. 280-289 ◽  
Author(s):  
Daen Wang ◽  
Theo G. Keith ◽  
Qingmin Yang ◽  
Vaidyanathan Kumar
Keyword(s):  
High Speed ◽  
Connecting Rod ◽  
High Speed Engine ◽  
Engine Part ◽  
Speed Engine

scholarly journals Model Reduction of the Flexible Rotating Crankshaft of a Motorcycle Engine Cranktrain

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Stefano Ricci ◽  
Marco Troncossi ◽  
Alessandro Rivola
Keyword(s):  
Model Reduction ◽  
Mode Selection ◽  
Normal Modes ◽  
Selection Procedure ◽  
Element Model ◽  
Multibody Model ◽  
Fixed Interface ◽  
Model Reduction Technique ◽  
Rigid Multibody ◽  
Motorcycle Engine

This paper addresses the development of an elastodynamic model of a motorcycle engine cranktrain aimed at accurately evaluating the interactions between the crankshaft and the engine block, thus allowing an improved structural design. A rigid multibody model is first implemented and simulated; only kinematic joints are involved at this stage, leading to a statically determinate assembly of the mechanism. Such a modelling approach prevents the loads at certain interface locations to be evaluated; furthermore, high-frequency dynamic effects cannot be predicted. These drawbacks can be removed by introducing bushing-like elements and/or modelling component flexibility. In this paper, this latter aspect is the objective of the investigation; in particular, a finite element model of the crankshaft is implemented as a replacement for the corresponding rigid member. The well-established Craig-Bampton model reduction technique is used to represent the elastodynamic behaviour of the component with a limited number of coordinates. The mode selection procedure is emphasized here: a measure of modal dynamic importance, namely the effective interface mass fraction, is used to rank fixed-interface normal modes based upon their contribution to loads at the substructure interface; choosing the modal base according to such ranking leads to a minimal yet accurate representation.

NONLINEAR SIMULATION OF A HIGH-SPEED, VISCOUS LIQUID JET

1998 ◽  
Vol 8 (2) ◽  
pp. 155-178 ◽  
Author(s):  
J. H. Hilbing ◽  
Stephen D. Heister
Keyword(s):  
Viscous Liquid ◽  
High Speed ◽  
Liquid Jet ◽  
Nonlinear Simulation

Analysis of the Lubrication Regimes at the Small End and Big End of a Connecting Rod of a High Performance Motorbike Engine

2012 ◽  
Author(s):  
Luca Bertocchi ◽  
Matteo Giacopini ◽  
Daniele Dini
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
High Performance ◽  
Hydrodynamic Lubrication ◽  
Vertical Axis ◽  
Connecting Rod ◽  
Lubrication Regimes ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Squeeze Effect

In the present paper, the algorithm proposed by Giacopini et. al. [1], based on a mass-conserving formulation of the Reynolds equation using the concept of complementarity is suitably extended to include the effects of compressibility, piezoviscosity and shear-thinning on the lubricant properties. This improved algorithm is employed to analyse the performance of the lubricated small end and big end bearings of a connecting rod of a high performance motorbike engine. The application of the algorithm proposed to both the small end and the big end of a con-rod is challenging because of the different causes that sustain the hydrodynamic lubrication in the two cases. In the con-rod big end, the fluid film is mainly generated by the relative high speed rotation between the rod and the crankshaft. The relative speed between the two races forms a wedge of fluid that assures appropriate lubrication and avoids undesired direct contacts. On the contrary, at the con-rod small end the relative rotational speed is low and a complete rotation between the mating surfaces does not occurs since the con-rod only oscillates around its vertical axis. Thus, at every revolution of the crankshaft, there are two different moments in which the relative rotational speed between the con-rod and the piston pin is null. Therefore, the dominant effect in the lubrication is the squeeze caused by the high loads transmitted through the piston pin. In particular both combustion forces and inertial forces contribute to the squeeze effect. This work shows how the formulation developed by the authors is capable of predicting the performance of journal bearings in the unsteady regime, where cavitation and reformation occur several times. Moreover, the effects of the pressure and the shear rate on the density and on the viscosity of the lubricant are taken into account.

The Coupling Characteristic of HSK Tool-Holder/Spindle Interface for High-Speed NC Machine Tool

2014 ◽  
Vol 590 ◽  
pp. 121-125 ◽  
Author(s):  
Wen Kai Jie ◽  
Jian Chen ◽  
Deng Sheng Zheng ◽  
Gui Cheng Wang
Keyword(s):  
Machine Tool ◽  
Rotational Speed ◽  
High Speed ◽  
Nonlinear Finite Element Method ◽  
High Rotational Speed ◽  
Tool Holder ◽  
Nc Machine Tool ◽  
Machine Tool Accuracy ◽  
Nc Machine ◽  
Coupling Characteristic

The coupling characteristic of the tool-holder/spindle interface in high speed NC machine has significant influence on machine tool accuracy and process stability. With the example of HSK-E63, based on nonlinear finite element method (FEM), the coupling characteristic of the tool-holder/spindle interface under high rotational speed was investigated, the influence of interference, clamping force and rotational speed on the contact stress and the sectional area of clearance were discussed in detail. The results can be used as theoretical consideration to design and optimize the high speed tool-holder/spindle interface.

Circuit Breaker Mechanical Characteristic Parameters Measurement Based on Machine Vision

2014 ◽  
Vol 687-691 ◽  
pp. 934-937
Author(s):  
Shu Tao Zhao ◽  
Yu Tao Xu ◽  
Zhi Wan Cheng ◽  
Jian Feng Ren ◽  
Dan Jiang
Keyword(s):  
Mechanical Characteristic ◽  
Template Matching ◽  
High Speed ◽  
Circuit Breaker ◽  
Motion Pictures ◽  
Time Interval ◽  
Connecting Rod ◽  
Characteristic Parameters ◽  
Coordinate Changes ◽  
Parameters Measurement

Aim at the disadvantages of traditional circuit breaker mechanical characteristic parameters test. Get the motion pictures of insulation connecting rod through high-speed camera, using the finite difference method to quickly screen out the motion pictures, and selecting punctuation area as a template for learning, using non-uniform sampling have a template matching, obtain the center coordinates of matching results, time interval is known every frame. Through coordinate changes over time we can obtain mechanical parameters of the circuit breaker accurately, fast, conveniently. Lab VIEW programs achieve the above process automatically.

Comprehensive design methodology for an engine journal bearing

2000 ◽  
Vol 214 (4) ◽  
pp. 401-412 ◽  
Author(s):  
H Hirani ◽  
K Athre ◽  
S Biswas
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Design Methodology ◽  
Design Procedure ◽  
Maximum Pressure ◽  
Connecting Rod ◽  
Automotive Engine ◽  
Reciprocating Engine ◽  
High Power Output ◽  
Minimum Film Thickness

The trend towards high power output, high speed and low power loss in engines requires a better understanding of bearing behaviour. Research in this area is directed more towards different aspects involved in bearing analyses, rather than providing a comprehensive guideline on design of bearing. This effort compiles the design methodology for selection of diametral clearance and bearing length by limiting the minimum film thickness, maximum pressure and temperature. The design procedure is summarized on the basis of the existing rapid bearing analyses for evaluation of the journal trajectory, minimum film thickness and maximum pressure and simplified thermal analysis. A flow chart is provided for step-by-step bearing design. Finally, two case studies of engine bearings are described: one investigates the VEB bigend connecting-rod bearing for a large industrial reciprocating engine and the other a main crankshaft bearing for an automotive engine. The methodology translates into easy-to-use expressions and the overall procedure is outlined, using practical data to demonstrate how this can be employed effectively by users.

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